Magnetic shields are often used to prevent extraneous magnetic fields from affecting display tubes.
For instance, Japanese Patent Application JP-88/13238 generally discloses a known shield having two parts separately secured to a supporting frame of a shadow mask. The facing ends of the parts are connected together by strips of frit glass or a similar material.
European Patent Application EP0518431 generally discloses another known magnetic shield that includes two complementary magnetic members positioned a distance from each other. Electron beams generated in a display tube are thus shielded from external magnetic fields, such as the earth's magnetic field. The level of magnetic shielding can be optimized by adjusting the distance between the two magnetic parts.
Known shielded electrical connectors are typically used in electromagnetically (EM) active environments. Examples of these environments include connections between two or more legs of a power or signal line, where the presence and consequent effects of an active EM-field (EMF) may be undesirable. Known shielded electrical connectors are employed to protect an external environment from the EMF generated within the connector, or to protect the internals of the connector from an external EMF.
Typically, in order to properly shield a connector housing, the connector and the complementary mating connector both have a shield member, i.e. made of a metallic conductive material, and both shield members contact and overlap with each other in order to achieve mechanical and electrical continuity, thereby achieving the shielding effect.
Static environments are less demanding on the shield as compared to non-static environments in which the connector housing may be subjected to movements and vibrations. In non-static or vibrating environments, the shield components may rub against each other when there are two parts separately secured to different ‘anchor’ locations in contact. The resulting abrasion between the shield components often produces metallic remnants such as a powder or shards/slivers. The metallic remnants can compromise the electrical separation of the shield by connecting the shield to a ‘live wire’ that may cause a short circuit, or can create electrical connections between other locations within the connector which might be undesirable and a cause for failure.
A further disadvantage of known shielded connectors in non-static environments is the ease in which the movement or vibrations are transmitted to other parts of the electrical circuit through the usually rigid shield. Movement or vibrations to other parts of the circuit can damage components incapable of functioning correctly in non-static environments. Prolonged exposure to such stresses can cause these components to prematurely fail.
Another disadvantage of known shielded connectors is that mechanical stress can be conducted through the shield to various locations where the shield is anchored to the connector, such as the location where the shield is crimped onto a cable. Over prolonged exposure, the mechanical stresses can cause the shield crimp to loosen and cause the shield crimp to fail altogether.